At one third of an ounce, 3BaysGSA PRO is the world"s lightest golf swing analyzer, which fits perfectly to the end of golf club and uses advanced motion sensors to digitize your swing motion instantly and deliver real-time animated swing plane playback along with key swing metrics to your smartphone or tablet on GSA PRO app. Golfers can compare each swing with their best ones or instructors" so they can make adjustments and improvements and thus pursue more powerful, accurate and consistent swings.